What is an arc flash?

There are many different hazards present in the workplace, but for many facilities, an arc flash has the potential to be the most dangerous. An arc flash is the arc of light and heat that is produced by electricity traveling through the air between two points. These happen when there is a path of low impedance outside of where the electricity is supposed to travel. For example, if there is a damaged high-voltage wire, the electricity can escape the wire and travel through the air to a ground point, or another conductor near the electrical system.

Arc flashes can occur in almost any electrical system regardless of how much electricity is traveling through. Even very weak electrical currents can cause a small flash, which wouldn’t be able to injure people in most situations. With even moderate electrical current, however, the arc flash can quickly become extremely dangerous, potentially causing burns, fires, blinding light, electrocution, and more.

About the Arc Flash

For high-voltage arc flashes, the temperature of the flash itself can exceed 35,000 degrees Fahrenheit. These temperatures are high enough to melt metal, immediately ignite wood or other combustible materials, and of course, cause extreme burns to anyone in the area.

The size of the arc flash will depend on a number of factors including the amount of current in the system. Low-current arc flashes are tiny and can barely be seen. Arc flashes in high-voltage systems, however, can extend many feet across, creating an incredibly dangerous situation throughout the area.

If the arc flash is sufficiently large, it can cause an explosion that can throw heavy objects in the area long distances, which further extends the potential damage. When this occurs, it is called an arc blast and is considered by many to be among the most dangerous events that can occur in many workplaces.


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